Meteorologists calculate Convective Available Potential Energy, or CAPE, by analyzing vertical profiles of temperature and moisture in the atmosphere. This process involves looking at a parcel of air and determining how much warmer and more buoyant it is than the surrounding air as it rises through the atmosphere.
The calculation is essentially an integral of the buoyancy force from the Level of Free Convection up to the Equilibrium Level. When a parcel of air is warmer than the air around it, it is less dense and rises naturally. The higher the temperature difference between the rising parcel and the environmental air, the greater the upward force and the higher the CAPE value. This value is measured in Joules per kilogram (J/kg).
High CAPE values indicate that the atmosphere has significant energy available to fuel strong updrafts. These powerful updrafts are the engines behind severe weather, capable of producing large hail, heavy rain, and intense thunderstorms. While high CAPE is a critical indicator of potential instability, meteorologists must also consider wind shear and lift to accurately predict whether a storm will become severe.
